Security vulnerability checking site makes your bitcoion insecure

(sorry for the typo in the title, my bad, smartphone fat finger artefact...)

The site keybleed.com wants you to submit your public key to check whether your wallet is insecure.

The problem: Your bitcoin wallet might be secure until the moment you disclose its public key, so using this site can actually be the true security risk.

In detail: Imagine you have created a Bitcoin address and stored a Bitcoin fortune in that address. Never ever were any bitcoins sent from this address. Under these circumstances, the public key was never disclosed in any way, only a concatenated hash of hashes of this public key, the Bitcoin address, was published.

Now when you disclose the public key, you make your Bitcoin address less secure. For example a quantum computer could calculate the private key from the public key, but not from the Bitcoin address.

So I'd think twice before using the keybleed.com site's service.